Wastewater cleaning system and process

A wastewater treatment system comprising:

• a vessel having an inlet and an outlet;
• a pump in fluid communication with the outlet of the vessel, the pump configured to pump wastewater out of the vessel;
• a hydraulic mixing system configured to impart a motive force on wastewater contained in the vessel, the hydraulic mixing system including nozzles disposed within the vessel and configured to generate plumes of wastewater that sweep a bottom of the vessel and create a rotating toroidal flow pattern of the wastewater within the vessel;
• a separator in fluid communication with the pump, the separator configured to separate grit from the wastewater, the separator having a first outlet for discharging a grit stream and a second outlet for discharging a wastewater stream;
• a grit washing system in fluid communication with a source of washing fluid and the first outlet of the separator, the grit washing system configured to wash and dewater grit from the grit stream, the grit washing system having an outlet for discharging a wash wastewater stream;
• a return conduit configured to recycle the wastewater stream discharged from the separator to one of the inlet of the vessel and an inlet to the pump;
• and
• a controller configured to control the pump to remove the wastewater from the vessel for a predetermined length of time, the predetermined length of time based at least in part on an accumulation rate of the grit in the vessel.